net: genetlink: push doit/dumpit code from genl_family_rcv_msg

Currently the function genl_family_rcv_msg() is quite big. Since it is
quite convenient, push code that is related to doit and dumpit ops into
separate functions.

Do small changes on the way, like rc/err unification, NULL check etc.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/genetlink.c

@@ -498,95 +498,76 @@ static int genl_lock_done(struct netlink_callback *cb)
 	return rc;
 }
 
-static int genl_family_rcv_msg(const struct genl_family *family,
-			       struct sk_buff *skb,
-			       struct nlmsghdr *nlh,
-			       struct netlink_ext_ack *extack)
+static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
+				      struct sk_buff *skb,
+				      struct nlmsghdr *nlh,
+				      struct netlink_ext_ack *extack,
+				      const struct genl_ops *ops,
+				      int hdrlen, struct net *net)
 {
-	const struct genl_ops *ops;
-	struct net *net = sock_net(skb->sk);
-	struct genl_info info;
-	struct genlmsghdr *hdr = nlmsg_data(nlh);
-	struct nlattr **attrbuf;
-	int hdrlen, err;
-
-	/* this family doesn't exist in this netns */
-	if (!family->netnsok && !net_eq(net, &init_net))
-		return -ENOENT;
-
-	hdrlen = GENL_HDRLEN + family->hdrsize;
-	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
-		return -EINVAL;
+	int err;
 
-	ops = genl_get_cmd(hdr->cmd, family);
-	if (ops == NULL)
+	if (!ops->dumpit)
 		return -EOPNOTSUPP;
 
-	if ((ops->flags & GENL_ADMIN_PERM) &&
-	    !netlink_capable(skb, CAP_NET_ADMIN))
-		return -EPERM;
-
-	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
-	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
-		return -EPERM;
-
-	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
-		int rc;
-
-		if (ops->dumpit == NULL)
-			return -EOPNOTSUPP;
-
-		if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) {
-			int hdrlen = GENL_HDRLEN + family->hdrsize;
-
-			if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
-				return -EINVAL;
+	if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) {
+		if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+			return -EINVAL;
 
-			if (family->maxattr) {
-				unsigned int validate = NL_VALIDATE_STRICT;
-
-				if (ops->validate &
-				    GENL_DONT_VALIDATE_DUMP_STRICT)
-					validate = NL_VALIDATE_LIBERAL;
-				rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen),
-						    nlmsg_attrlen(nlh, hdrlen),
-						    family->maxattr,
-						    family->policy,
-						    validate, extack);
-				if (rc)
-					return rc;
-			}
+		if (family->maxattr) {
+			unsigned int validate = NL_VALIDATE_STRICT;
+
+			if (ops->validate & GENL_DONT_VALIDATE_DUMP_STRICT)
+				validate = NL_VALIDATE_LIBERAL;
+			err = __nla_validate(nlmsg_attrdata(nlh, hdrlen),
+					     nlmsg_attrlen(nlh, hdrlen),
+					     family->maxattr, family->policy,
+					     validate, extack);
+			if (err)
+				return err;
 		}
+	}
 
-		if (!family->parallel_ops) {
-			struct netlink_dump_control c = {
-				.module = family->module,
-				/* we have const, but the netlink API doesn't */
-				.data = (void *)ops,
-				.start = genl_lock_start,
-				.dump = genl_lock_dumpit,
-				.done = genl_lock_done,
-			};
+	if (!family->parallel_ops) {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			/* we have const, but the netlink API doesn't */
+			.data = (void *)ops,
+			.start = genl_lock_start,
+			.dump = genl_lock_dumpit,
+			.done = genl_lock_done,
+		};
 
-			genl_unlock();
-			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-			genl_lock();
+		genl_unlock();
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+		genl_lock();
 
-		} else {
-			struct netlink_dump_control c = {
-				.module = family->module,
-				.start = ops->start,
-				.dump = ops->dumpit,
-				.done = ops->done,
-			};
+	} else {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			.start = ops->start,
+			.dump = ops->dumpit,
+			.done = ops->done,
+		};
+
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+	}
 
-			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-		}
+	return err;
+}
 
-		return rc;
-	}
+static int genl_family_rcv_msg_doit(const struct genl_family *family,
+				    struct sk_buff *skb,
+				    struct nlmsghdr *nlh,
+				    struct netlink_ext_ack *extack,
+				    const struct genl_ops *ops,
+				    int hdrlen, struct net *net)
+{
+	struct nlattr **attrbuf;
+	struct genl_info info;
+	int err;
 
-	if (ops->doit == NULL)
+	if (!ops->doit)
 		return -EOPNOTSUPP;
 
 	if (family->maxattr && family->parallel_ops) {
@@ -638,6 +619,44 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 	return err;
 }
 
+static int genl_family_rcv_msg(const struct genl_family *family,
+			       struct sk_buff *skb,
+			       struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	const struct genl_ops *ops;
+	struct net *net = sock_net(skb->sk);
+	struct genlmsghdr *hdr = nlmsg_data(nlh);
+	int hdrlen;
+
+	/* this family doesn't exist in this netns */
+	if (!family->netnsok && !net_eq(net, &init_net))
+		return -ENOENT;
+
+	hdrlen = GENL_HDRLEN + family->hdrsize;
+	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+		return -EINVAL;
+
+	ops = genl_get_cmd(hdr->cmd, family);
+	if (ops == NULL)
+		return -EOPNOTSUPP;
+
+	if ((ops->flags & GENL_ADMIN_PERM) &&
+	    !netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
+	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
+		return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
+						  ops, hdrlen, net);
+	else
+		return genl_family_rcv_msg_doit(family, skb, nlh, extack,
+						ops, hdrlen, net);
+}
+
 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			struct netlink_ext_ack *extack)
 {